<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
		<!-- 最新版本的 Bootstrap 核心 CSS 文件 -->
		<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
	      
	      <style type="text/css">
	      	.p{
	      		width: 200px;
	      		height: 200px;
	      		color: white;
	      		background-color:blue ;
	      	}
	      </style>
	</head>

	<body>
		<a class="btn btn-default" href="#" role="button">Link</a>
		<button class="btn btn-default" type="submit">Button</button>
		<input class="btn btn-default" type="button" value="Input">
		<input class="btn btn-default" type="submit" value="Submit">
		<button type="button" class="btn btn-danger">危险</button>

		<p class="btn btn-danger visible-xs-block">123</p>

		<p class="text-left">Left aligned text.</p>
		<p class="text-center">Center aligned text.</p>
		<p class="text-right">Right aligned text.</p>
		<p class="text-justify">Justified text.</p>
		<p class="text-nowrap">No wrap text.</p>
		
		<p class="p text-center">123</p>
		
		<p class="text-uppercase">Uppercased text.</p>

	</body>

</html>